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Alpine MRX-M55

Mono subwoofer amplifier — 550 watts RMS x 1 at 2 ohms

26 Reviews | 2 questions - 9 answers

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Item # 500MRXM55

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Our take on the Alpine MRX-M55

Alpine's X-Power MRX-M55 mono amplifier uses the latest amp technology to play your music loud and clean without taking up much space. And this amp employs some of the same circuitry developed for Alpine's top-of-the-line PDX digital amps, so it'll bring exceptional sound to almost any ride.

Alpine Authorized Online Dealer

Digital technology that sounds perfect

Alpine's X-Power MRX-M55 mono amplifier uses the latest amp technology to play your music loud and clean without taking up much space. And this amp employs some of the same circuitry developed for Alpine's top-of-the-line PDX digital amps, so it'll bring exceptional sound to almost any ride.

Big power for big bass

The MRX-M55 puts out up to 550 watts RMS to your subwoofer system, so you can fill your listening space with plenty of bass. And it'll even operate safely with a 1-ohm load, making it useful in a variety of sub system installations. Onboard low-pass and subsonic filters let you get the best sound out of your setup, while a bass boost helps to fatten up the sound if you need it.

Keep the music playing

A power management system optimizes the amp's performance and keeps the music playing, even when you're pushing it hot and hard for a long time. Speaker-level inputs with an automatic turn-on feature simplify system hook-up.

MRX-M55 control panel

Confused about impedance? Check out our article on matching subs and amps.

Product Highlights:

  • mono subwoofer car amplifier
  • 350 watts RMS x 1 at 4 ohms (550 watts RMS x 1 at 2 ohms)
  • 400 watts RMS x 1 at 1 ohm
  • CEA-2006 compliant
  • variable low-pass filter (50-400 Hz, 24 dB/octave)
  • variable bass boost (0-12 dB at 50 Hz)
  • variable subsonic filter (5-30 Hz, 24 dB/octave)
  • optional remote level control (RUX-KNOB)
  • Class D amp with MOSFET power supply
  • preamp and speaker-level inputs
  • preamp outputs
  • fuse rating: 30A x 2
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 9-15/16"W x 2-5/16"H x 9-1/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • Mono amplifier with two 30A fuses installed
  • Left plastic terminal cover
  • Right plastic terminal cover
  • 4 Terminal cover screws (M3 x 10mm)
  • 4 Self-tapping screws (M4 x 20mm)
  • 2.5mm Allen wrench
  • 7" Speaker-level input harness
  • Owner's Manual (Eng/ Fren/ Span)
  • Warranty sheet
  • Online registration card
  • Alpine Verification Certificate

Featured Video:

One of the best amps i have ever owned .

Daniel, Electra TX


Alpine MRX-M55 Reviews

Average Customer Review(s):

(26 Reviews)

Alpine MRX-M55

Daniel from Electra TX on 5/22/2017

One of the best amps i have ever owned .



Great amp!

Jay from Colorado on 2/27/2015

Crutchfield Customer Review (What's this?)

Great amp! Setup was simple, runs cool, and does everything I need it to do. Running a single 12" sub currently, no issues whatsoever.

Pros: Everything. I just needed a good mono amp to push a ~300 rms 12" sub, and it does so perfectly. Having both low pass and subsonic filters lets me dial in the exact range I want to work in.

Cons: None, really. Very solid choice if you need a moderately-powered amp!

Excellent Amp

Chris from New Jersey on 12/29/2014

Crutchfield Customer Review (What's this?)

Hi all. bought this to replace a several year old Kicker Ix500.1. Using the Same Subwoofer (JL W3v3 2Ohm Sealed box), Its like Day and Night. The Subwoofer seemed to wake up. Just need to Tweak it. And don't know Why, Alpine used Aluminum Wires on the Speaker Level Input?? Made a but tricky to solder the connections.

Pros: Good Size. Powerful. Speaker Level Input (Factory HU). Tested at 578 Watts RMS (2ohm)

Cons: Aluminum Speaker Input leads?? No Remote Lead output. Cant activate the voltmeter on my capacitor until I run another wire.

alpine amp

Bigdumy from New Jersey on 12/20/2014

Crutchfield Customer Review (What's this?)

the best of the rest... clarity is what I strive for, and it is what I got from alpine... awesome amp, loud, and easy to connect... BUY IT!!!!

Pros: best

Cons: none

delivers the power

Dan from Vermont on 12/17/2014

Crutchfield Customer Review (What's this?)

Does what it is supposed to




Kyle from Apo,Ae on 12/8/2014

Crutchfield Customer Review (What's this?)

Tons of power bought two of these to power my two ten inch subs and man do they hit deeper and have such a better tone to them then my previous amp did. I haven't even had a chance to properly tune them yet due to the fact I just got in my new mids and highs in the mail today!

Pros: Very smelly and compact pack one hell of a punch!

Cons: None simply amazing

Perfect Match

Justin J. from Newport News, Va on 11/24/2014

Crutchfield Customer Review (What's this?)

Got this to round out my system in my 04 TL. It's running a single sws-12d4 in a sealed box beside a mrx-f35 and polk dxi components. Wiring was easy, and setup is flexible letting me dial in just the right ammount of thump. Rated power is 609watts @ 2 ohms. Running the sub @ 2ohms i get impressive response and tight control. This is my first system to use a sub but it's my 3rd Alpine amp. Didn't even consider anything else. For an enthusiast (not a competition or "audiophile" grade) system I couldn't be happier.

Pros: Small footprint, great power, cool running and responsive

Cons: Can't think of one.

Always loved alpine

Joe from Holly, mi on 11/23/2014

Crutchfield Customer Review (What's this?)

This amp is great. Have it pushing a 10" mb quart at about 375 rms (guessing) at 1 ohm and its pretty loud! Gives enough power to play heavy bass songs with ease. gain set to about an eighth of the way. Gunna hook it up to a type s (12d2) that takes 500w RMS at 1 ohm and i know it will preform well. I have never found a brand in this price range to beat alpine. There stuff is perfect for almost anyone. Trust this brand and the crutchfield staff!

Pros: Powerful, very small, blue led looks sweet in trunk, easy to install and tune

Cons: So far none

mrp m500

leroy from mississippi on 11/19/2014

i have the alpine mrp m500 hooked to a pair of champion series pioneer 12s in sealed box.....for a while it bumped so hard it would knock the wind out your ears and this was when the radio on 15 and the amp half way...after a month they sound like 10s...subs wasnt blown no wires lose....guess i broke em in.....but i put in my focus wagon they sound like 15s....mayby i need to go bigger in my magnum

Pros: mrp m 500 sound good with 2 12in pioneer champion series in 2014 focus wagon

Cons: imma have to go with a bigger alpine and subs for my magnum...i shoulda kept my mtx 1000.1d for the magnum

Alpine MRX-M55

Justin from San Antonio, Tx on 11/17/2014

Crutchfield Customer Review (What's this?)

Great Bass. Great Customer Service



Great Amp (If Yours Doesn't Have Problems)

Brad from Northern VA on 10/30/2014

Crutchfield Customer Review (What's this?)

I would like to preface this review by saying that if you get one of these amps and it functions correctly, then you will be a very happy consumer. It looks great, installs easily, and has some nice features. My story (I'll give you the short version) has not been so nice. The first amp I received was broken right out of the box (knobs would spin infinitely). Crutchfield replaced that, no problem (best customer service). A few weeks later, the bass would randomly start cutting out while I was driving. I spent weeks looking into BT issues with my car and phone, troubleshooting power and ground to the amp, and looking into various causes with Cruthfield techs. In the end, I was told that I most-likely have a defective amp and need to contact Alpine. Call Alpine and you have to pay to send them the amp, they will "test" it and send it back fixed (or new if unfixable). So, I'm now riding around with no bass (again) after purchasing this amp at full price (it wasn't on sale when I bought it). I'm sure they're going to send the amp back as-is because they won't be able to replicate my intermittent problem, and I'm going to toss it straight in the trash. Take this review with whatever amount of salt you feel is necessary, but I have had a horrible experience with Alpine electronics (used to be my go-to amp company) and I will have to think very hard before I buy something from them again.

Pros: Sleek Looks Small Size Features (subsonic filter, speaker-level inputs, etc)

Cons: Horrible Alpine Customer Service Terrible Build Quality

Great amp

DeKees1 from Tampa fl on 10/22/2014

I have this amp runnin my 10in alpine sub and it hits hard and sounds so clean in my 06 Vw rabbit. Haven't had any issues with it in the last almost year now.



Power house

Jimmy from Greenfield on 10/8/2014

Crutchfield Customer Review (What's this?)

Small size but powerful amp , very reliable, I travel for hours daily and have the tunes going the whole time .

Pros: Compact size , very powerful , tons of adjustment .

Cons: None

Excellent for driving my 10"

Samuel L from Dublin, CA on 9/24/2014

Crutchfield Customer Review (What's this?)

Plenty of power to drive a dual voice coil 10" in a sealed enclosure. Gain is @ 50% and it sounds great! Foot print of amp is small and easy to place in my trunk.

Pros: Efficient, great value for the money. Crutchfield advisors guided me to this amp, they where patient and answered all my questions.

Cons: none

alpine mrx m55

anonymous from Somewhere, USA on 9/20/2014

Crutchfield Customer Review (What's this?)

Good amp. No issues so far

Pros: sounds clean

Cons: None so far

Great Amp

joshua L from corpus christi, TX on 8/31/2014

Crutchfield Customer Review (What's this?)

Great Amp pretty small fits right under sit in a 09 Silverado single cab and delivers great clean power birth sheet was 592W at 2 ohms

Pros: great size and power

Cons: none

Great amp

Stephen b. from Coaling on 8/20/2014

Crutchfield Customer Review (What's this?)

So far so good. Real nice compact size. Give you everything you need .




Jack from Augusta, GA on 7/2/2014

Crutchfield Customer Review (What's this?)

Great amp. It's paired with a 10" R series sub, and it hits hard and tight.

Pros: Crossover and eq adjustments



kungfucious from Carlsbad, CA on 6/28/2014

Crutchfield Customer Review (What's this?)

Works perfect, big power, small amp :-)



Power to the sub

RMJ from Fredericksburg,VA on 6/24/2014

This amp give the sub that awesome kick so you know it's there.

Pros: Neat little powerhouse.

Cons: None


Jodyd from Louisiana on 10/22/2013

Crutchfield Customer Review (What's this?)

I bought this amp to replace my alpine mrp-m500 (a friend wanted to buy it from me). It has a little more power not sure if it's dramatically more though. It plays very clear. It is definitely an upgrade do to the ability of being able to add a remote, the subsonic setting, and 50 more rms watts. The size is also smaller, I was very surprised when I unboxed it. I have it pushing an alpine type r 10" in a ported box in my 2012 super crew f150. I'm definitely under powering the sub but it still sounds awesome clean sound go alpine!

Pros: Small, powerful, flexibility in settings

Cons: None

more then enough!!

Mark H from Cincinnati, OH on 9/17/2013

Crutchfield Customer Review (What's this?)

I purchased 2 of these for 3 subs. 2 10in dvc for 1 and being 1ohm stable makes for great power to feed these subs.They've never hit so hard. And the other amp i purchased with the seprate gain contol knob to feed 1 400w dvc. All subs are JBL. there is no substitute. Very impressed with both amps.Neither 1 runs hot. customer service with brooke was great. She even tryed to save me money.

Pros: Very powerful. Like the connection style better then the older models. Makes for easier and cleaner install.

Cons: Its not really a con nor a complaint. but when buying 2 of the same amps. The date of birth on 1 says 595 watts and the other says 623 watts. its just one of those odd and curious whys? but it does also say 550min.

606 watts @ 2ohms birth sheet

bman from OK on 4/26/2013

Crutchfield Customer Review (What's this?)

Easy install and setup. Only pushing a single DVC 10" Stype and it doesn't break a sweat.

Pros: plenty of power

Cons: none so far

it pounds

badboyb from Given, WV on 4/22/2013

Crutchfield Customer Review (What's this?)

This amp will handle pushing dvc subs and is 1 ohm stable ! Nice

Pros: Easy to hook up.


575rms@2ohm birth sheet

meNurma from ohio on 7/2/2012

Crutchfield Customer Review (What's this?)

as title states birth sheet claims 575rms @2ohms thats kinda disapointing as Alpine states on there website "Each amp comes with their very own verification certificate documenting its actual power output exceeds the rating by a wide margin" Umm 25 watts more isn't a wide margin to me. I have the gain almost all the way up and also using the OPTIONAL bass knob control and it's not hitting as hard as i would like but that could be from multiple problems bad amp or just simply needs tuned better etc etc. My lights seem to not dim that much i'm running a OEM 120amp alt and a Optima yellow top as my main car battery that's it. Hooked up to one Alpine Type R 4th gen wired @2ohms in a Sound Ordnance sealed .95ft box filled with polyfill

Pros: clean power , small footprint

Cons: bass knob not included , 1 year warranty unlike other brands with 2 years in this price range

Nice Amp!

Joey from Clarksville, Md on 6/22/2012

Crutchfield Customer Review (What's this?)

Very nice amp. Using this amp to power a 15" sub in a sealed box. Plenty of power to drive it. Alpine sent out a verification certificate which shows actual output power(RMS) at 630 watts at 2 ohms. Sound quality is very clean. Cool running amp also. I have had this amp only a few weeks , but so far so good...

Pros: Size, power, cost and clean sound...



Hands-on research

Product Research



MRX Amplifier Design: Class-D amplifiers boast higher efficiency, produce less heat, and draw less current than traditional Class-AB amps. The MRX series benefits from the technology trickledown from Alpine's more expensive PDX amps, including Direct FET final outputs, thermal management processor, 6-Layer Glass Epoxy PC Board; combining to create a high-end sound quality without the bulky heat sinks required by most amps in this power class.

STAR Topology: Alpine's unique STAR (Signal Transit for Accurate Response) Circuit PCB design provides a single common ground for all amp sub-blocks, preventing ground interference and minimizing internal noise.

Power Management Processor: The multi-stage Power Management Processor continuously monitors component temperatures throughout the amplifier and decreases power output if anything gets too hot. When playing music under heavy loads for long periods, the circuit automatically reduces power output slightly at first, and then further in a second stage if necessary. This two stage approach provides an interruption free listening experience.

CEA 2006 Compliant: The MRX-M55's power ratings are measured according to the Consumer Electronics Association CEA-2006 standards. These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging. The power output is measured from 20 Hz to 400 Hz using a 14.4 volt power supply with no more than 0.01% THD+N:

  • 4-ohm: 350 watts
  • 2-ohm: 550 watts
  • 1-ohm: 400 watts

Signal-to-Noise: When measured under CEA-2006 conditions (reference 1 watt into a 4-ohm load) the signal to noise ratio is 90 dBA. Measured at the rated power output S/N is 114 dB.

Verification Certificate: The amplifier comes with a certificate that lists the RMS power output measured from that specific amplifier. It also lists the model number, serial number, test date, and the test conditions (voltage and impedance).

Auto Turn On: When using the speaker level inputs the X-Power amplifiers automatically turn on when voltage is detected on the signal inputs, making them an easy factory system upgrade.

Low Output Impedance: With low output impedance, the MRX-M55 outputs tightly controlled bass, with a damping Factor rated at greater than 1000.

LED: The top panel LED power indicator glows blue when the amplifier is turned on.


Gain: The MRX-M55's gain is set according to the level of the incoming signal. The line-level input gain setting is continuously variable from 100 mV to 4.0V; the speaker-level input gain setting is continuously variable from 250 mV to 10.0V.

Crossover: The low-pass crossover point is continuously variable from 50 to 400 Hz and the slope is 24 dB/oct; the crossover cannot be bypassed.

Subsonic Filter: The amp also has a 24 dB/oct subsonic filter, continuously variable from 5 to 30 Hz.

Bass EQ: Bass boost can be applied to the subwoofer output; it's variable from 0 to +12 dB and centered at 50 Hz.


Power/Ground/Remote: The MRX-M55 features set-screw terminals for the Power, Ground and Remote Turn-on inputs. The Power and Ground terminals will accommodate up to 4 gauge wire (Alpine recommends 4 gauge for cable runs over 3'), the Remote Turn-on terminal will accept up to 8 gauge wire.

Speaker Output: The speaker outputs terminal is also set-screw terminals and will accept up to 8 gauge wire.

Line Input/Output: Line level RCA is the preferred input connection. The full range stereo line output allows easily adding another amp without running a second set of cables.

Speaker Level Input: Use the included speaker level input harnesses if the connected radio has no preamp outputs.

Fuses: The amp is protected by two chassis mounted 30-amp ATO fuses.

Remote Bass Control (optional): Alpine's RUXKNOB wired remote (sold separately), connects to the amp's RJ-25 Remote Bass Control jack, and offers control of the subwoofer output level from the front of your vehicle. The linear attenuation can be adjusted from 0 to -20dB.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

2 questions already asked

I bought an 8 gauge amp kit locally, I think it was a Rockford Fosgate kit. They price matched it to online so it wasn't too expensive. As long as you stick with a name brand, you'll be fine. [ Charles  Aug 09, 2014 ]
I would use at least a 8 gauge or bigger power and ground wire, i used 4 guage. And yes you are gonna want a better quality install kit, because lower quality kits can cause unwanted noise in your system. You really need to pay attention to the RCA cables that go from the head unit to the amp that is where you are going to want a higher quality cable. Make sure to use at least a 12 guage wire from your amp to speakers, anything smaller can possibly cause your amp to shut down . By the way you should be very pleased with this amp, i have it pushing a single 12" alpine type R and it sound very good, almost hits harder than the 2 kicker 12" i use to have. Anyways good luck and i hope this helps [ Kevin  Aug 04, 2014 ]
4 gauge power wire with big in line fuse,4 gauge ground ,make sure the ground wire is as short as possible,depending on the speaker 8 to 12 gauge for the speaker wire, remote turn-on you can use a 16 gauge is fine :-) [ GREG  Aug 04, 2014 ]
Your wire gauge depends upon the length of wire you plan on using. For instance a short run (couple feet)you could get away with 8 or 6 gauge. A longer run (several feet) would require bigger wire like 4 or 2 gauge. The bigger the wire the easier it is for the amp to obtain the power it needs and the amp with also run cooler and more efficient. Stay away from cheap install kits, often times the wire they supply does not measure what it's labled. [ matthew  Aug 04, 2014 ]
I bought a 4 gauge wiring kit to go with it, and I'd works perfectly fine. The 4 gauge allowed plenty of power to flow through the amp with no distortion at all. [ Caleb  Aug 04, 2014 ]
Hi David E - we probably don't know each other but our vendor asked me to answer your questions so for what it's worth here you go: Q: What gauage wire? A: That depends. How far is the +12V source? In a typical vehicle the run is less than 20 feet so assuming the only device connected to the power lead is this amplifier then the size Alpine recommends is fine. I just happened to have enough 8g. on hand and installed this model in a Tacoma under the rear jump seats. Q: Kits vs SQ? A: Copper is copper so as long as the wire is the correct gauge there should not be a significant difference from one brand to the next. Kits usually include RCA type signal cables so this is where price can make a difference. Stay away from the budget kits that use little or no shielding and flimsy RCA connectors. You didn't ask but I'll offer this as advice for your installation. Grounding is more important than most folks understand. Use at least the same gauge wire as the battery lead and plan the mounting location out to keep the ground lead to a reasonable minimum - one or two feet if possible. Larger wires need proper crimp tools to attach the right type of connetor like a ring lug and then make sure to bolt the lug to bare metal and cover the area with silicone or spray paint to prevent rust. Hope this helps. Scott [ Scott  Aug 04, 2014 ]
4 gauge or 8 gauge , 4 gauge I believe it runs better and make sure you have a really really good ground, a lot of kits are the same just make sure you get the better gauge! [ BRAD  Aug 04, 2014 ]
I used 4 ga for power, 8 ga for ground, and 12 ga for my subwoofer. Everything works and sounds great. The power wire was bought as a kit with an inline fuse and RCA cables. [ MARK W  Aug 04, 2014 ]

1 answer Hi, I have an amp and a sub 1) the question is - how to wire them? Original thought was to run amp as 4 ohm @ 350W to 4 ohm sub @ 300W, but after some reading it is my understanding that only way to wire them is either at 2 or 8 ohm, parallel or series, 2) @ 2ohm the amp will output 550W to 300W sub, is it possible to tune it down, turn gain down or something? 3) if above doesn't work, would amp output 550W when head unit is turned all the way up? So if I turn it up half way, would it cause the amp to output ~275W ? 4) what will happen if I wire them as 8ohm? Thank you, Andrei. [ Andrei  Apr 08, 2014 ]

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the install. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: Or try our online support center: [ Krissy  Apr 08, 2014 ]  Staff